Most modern guns are provided with a white light optical sight or red dot sight. After the sight is installed, the gun needs to be calibrated prior to using it. The fundamental method is target shooting practice, i.e., the gun is calibrated after each shooting till the correct position is reached. This method wastes time and bullets. After that, a calibration mirror for gun, a laser red dot bullet and a muzzle laser red dot rod and the like are successively developed.
Among them, a muzzle laser red dot rod, as shown in FIG. 1, mainly consists of a straight bar 1 that is inserted into a barrel, a laser device 2 that is installed coaxially with the straight bar and in the rear end of the straight bar 1, and a battery cabin 3 that accommodates battery. This kind of gun calibrator has simple structure, and high adjustment accuracy of gun calibration, but has the following obvious defects: low amount of battery power, frequent replacement of battery, and poor concentricity of the gun calibrator with the barrel that leads to large errors.
Compared with the gun calibrator shown in FIG. 1, the gun calibrator shown in FIG. 2 has an annular limit elastic ring 29 that is displaced in a rear end portion of the straight bar 1 (that is, the end in which the laser device is not installed, i.e., the left side shown in this figure). The annular limit elastic ring 29 can ensure that the straight bar 1 is in close contact with the inner wall of a barrel. Further, there is a variable diameter section 30 in the center part of the straight bar 1 near the battery cabin 3. The variable diameter section 30 is a truncated cone with an increasing diameter toward the battery cabin 3 that gradually becomes larger than the inner diameter of the barrel to form limits on two ends together with an annular limit elastic ring 4, thereby effectively improving the coaxiality of the straight bar 1, the laser module 2 and the barrel. Further, the battery cabin 3 is relatively large (and integrated with the laser module 2), can accommodate batteries with a large volume, and thus, has a good battery endurance. However, a larger force, in particular gravity due to the battery with a large volume to be installed, is applied on the annular limit elastic ring 29 at the rear end thereof, resulting in an unavoidable phenomenon, i.e., the front end of the straight bar 1 is raised upwardly. Therefore, ideal coaxiality has not been reached yet.
Either the gun calibrator shown in FIG. 1 or the gun calibrator shown in FIG. 2 has a single function, i.e., providing a single light source for laser irradiation. The single laser type of gun calibrator is affected by the environmental, i.e., it can only be used indoors under dim light. In an outdoor environment under intense light, this type of gun calibrator cannot be used since the laser light point is blurred under the ambient light. Therefore, the scope of application is limited.